Machine For Bending Tubular Products and Tube Bending Machine

ABSTRACT

A machine to bend tubular elements comprising bending means provided with a bending arm and a bend core disposed, when in use, inside said tubular element. The bend core comprises a support bar, a contrasting ogive and a possible bend-follower element disposed articulated at the head of the contrasting ogive. The machine also comprises movement means to move said tubular element in a direction toward said bending means and cutting means to cut a segment of tube. The machine comprises holding means disposed on the perimeter around said tubular element and configured to maintain said bend core in a condition of suspension inside said tubular element.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns a machine to bend tubular products, forexample metal tubes to make fluid dynamic tubes, pipes, plants or other.In particular, the machine according to the present invention allows tobend such tubular products in an automated way and feed themsubstantially continuously onto a bend core.

The present invention also concerns the bending method for the tubularelements.

Here and in the following description and claims, by the term continuousfeed we mean a feed of the tubular product starting from a product in aroll or in a bar, but which in any case has a starting length higher inmultiples than the length of the segment which is the finished product.

2. Description of Related Art

Machines are known for the automatic or substantially automated bendingof tubular elements, which allow to make parts of pipes, plants, tubing,fluidic connections or other, according to different design bends.

The known bending machines for this type of product can be distinguishedinto substantially two groups, that is, bending machines with a core andbending machines without a core.

In particular, in bending machines with a core the tubular elements arepre-cut to size into segments and then loaded onto the machine to feedthem onto the core.

This type of known machine, although it guarantees a high bendingquality of large-size tubular elements with limited radiuses for eachbending operation, needs different auxiliary equipment both for thepreliminary cutting into segments and also for loading the segments ontothe core, prior to the bending steps.

This causes an increase in the costs of managing the machine and anincreased operating complexity and automation.

Moreover, very often, this type of known machine has a mainly manualuse, with consequent operating delays, the need for specializedpersonnel and an increase in production costs.

Moreover, known bending machines with a core, due to their conformationand operating conception, carry out a tail bending, that is, startingfrom the opposite end of the tube with respect to the end that is fed.

Tail bending, for many products, needs to provide that the length of thesegment is suitably longer than the length of the actual development ofthe tubular element once it is bent, since it is necessary that thesegment is still gripped by the part not bent during the execution ofthe last bend.

Some types of known bending machines are also characterized by theformation of high quantities of waste caused by short rectilinearsections of the end of the bent tubes.

The formation of waste has two main reasons. On the one hand, thetraditional machines with core, because of their operating conception,need the tube to be supported at one end, so that the section of tubewhich acts as a support causes waste to be eliminated at the end. On theother hand, waste is caused because, starting from the segment in thebending step, the external material stretches and creates a deformingeffect on the end of the cut tube, which obliges one section to beeliminated.

Coreless bending machines, on the contrary, are applied in particularfor bending tubular elements of reduced diameter with high radiuses, andfed from a roll.

These known machines, which provide a bending system with a matrix andclamp, and not a core, can entail, in the case where reduced radiuses ofcurvature are required, an ovalization of the usable section for thepassage of the tubular element, and the fluidic characteristics of thetubular element itself may vary.

In some conditions, a partial occlusion of the tubular element can occurat the bent point, with consequent lack of performance of the finalproduct.

BRIEF SUMMARY OF THE INVENTION

One purpose of the present invention is to produce a machine for bendingtubular elements which allows an efficient bending both of tubularelements with an ample diameter with reduced radiuses of curvature, andtubular elements of a limited diameter with ample bending radiuses.

A further purpose of the present invention is to make a machine forbending tubular elements which is simple and economic, which allowsgreat operating automation, which uses a bend core and can be fedsubstantially continuously.

Another purpose of the present invention is to perfect a method forbending tubular elements which overcomes the shortcomings of the stateof the art.

The Applicant has devised, tested and embodied the present invention toovercome the shortcomings of the state of the art and to obtain theseand other purposes and advantages.

The present invention is set forth and characterized in the independentclaims, while the dependent claims describe other characteristics of theinvention or variants to the main inventive idea.

In accordance with the above purposes, a machine for bending tubularelements according to the present invention comprises bending meansprovided with at least a bending arm able to act on an external surfaceof the tubular element in order to make a bend, and with a bend coreable to be disposed inside the tubular element to contrast from theinside the action of the bending arm, and to conform, in a desired way,the bend of the tubular element.

The machine according to the present invention also comprises movementmeans able to move the tubular element in a linear manner, both in thefirst feed step toward the bending means and also during the bendingsteps.

According to a characteristic feature of the present invention, thebending machine also comprises holding means selectively connected tothe bend core in order to keep the latter in a condition of substantialsuspension inside the tubular element.

The condition of suspension defined by the holding means is such thatthe movement means feed the tubular element toward the bending means ina direction and sense concordant with a work direction of the bendingmeans on the tubular element.

In this way, the tubular element is worked head-wise, that is, startingfrom the same end as that with which the tubular element is fed.

This work condition allows to feed the tubular element substantiallycontinually, exploiting the advantages of automation of known corelessmachines. Unlike these known machines, the machine according to thepresent invention, also exploits the advantageous characteristics ofusing the core to carry out the bending.

In this way, it is possible to provide a machine for bending tubularelements which is substantially automated, or can be automated, more orless completely, which allows to bend with both large and reducedradiuses, substantially of the whole dimensional range of tubularelements.

With the present invention there is a reduction in operating andmanagement costs of the machine, optimizing the yield.

According to a variant, the holding means are of the magnetic type, thatis, they provide at least a magnetic element disposed on the perimeteraround the zone where the tubular element is disposed in the operatingcondition. By magnetic element, here and in the following descriptionand claims, we mean any element suitable to exert a magnetic force ofattraction on an element, which is also magnetic, magnetized or hasmagnetic means (in this case the bend core), therefore includingpermanent magnets, electromagnets, elements which can be magnetized andany other element suitable for the purpose.

The at least one magnetic element, or the plurality of magneticelements, is/are disposed around the tubular element in order togenerate a magnetic field which keeps the core in a condition ofsuspension inside the tubular element.

The position of the magnetic element or elements is lateral, that is,not interfering with the axis of feed of the tubular element, and thisdetermines a considerable operating advantage, promoting the automationof the advance and feed movements of the tubular element toward thebending means.

The bending core is disposed axially in correspondence to the centralzone of magnetic balance, thus staying in a condition of substantialsuspension inside the space defined by the magnetic elements.

The tubular element is thus fed by the movement means in the directionof feed, inserting itself into the interspace defined between themagnetic elements and the bend core, without any interference by anypossible supports of the bend core or the tubular element itself. Inthis disposition, the tubular element is further fed by the movementmeans in the same direction and the same sense, in a manner coordinatedwith the drive of the bending means in order to carry out the bendsrequired.

In this solution, it is obvious that no working waste at all isproduced, in that once a first portion of tubular element has been bentaccording to the desired pattern, the tubular element can be cut exactlyto size, separating only the bent portion. In this condition, the tailend of the remaining tubular element coincides with the leading end ofthe new portion to be bent, and so on.

According to a variant, the magnetic elements can be conformed so as tocommand an axial recovery movement of the core after the bending steps.

According to another variant, the holding means comprise a firstgripping member disposed in cooperation with a first end, or tail end,of the bend core, and able to maintain the bend core in the suspendedcondition during the feed steps of the tubular element in the directionof feed.

In this variant solution, the holding means also comprise a secondgripping member disposed in cooperation with a second end, or tail end,of the bend core, and able to maintain the bend core in the suspendedcondition during the bending steps of the tubular element.

In this solution too, as in the previous one, the holding means aredisposed and act laterally with respect to the position of the tubularelement, so that there is no interference by the holding means withrespect to the axis of feed of the tubular element.

In this variant solution, the tubular element is initially fed head-wiseby the movement means. Then the tubular element is cut or sheared inorder to define a segment of desired length.

Subsequently the segment is fed along the direction of feed so as tofree the tail end of the bend core.

In this condition the second gripping member is activated and the firstgripping member is de-activated, so that the movement means can feed thesegment in the same direction and sense in order to bring it intocooperation with the bending means and carry out the bends required.

The suspended condition of the bend core is guaranteed at the rear bythe second gripping member.

With this variant, the bending occurs only on a segment coinciding withthe dimension of the development of the portion to be bent, so as tofacilitate the operations to move the segment, and to further improvethe quality results of the bend carried out.

According to a further variant, the holding means comprise a supportmember, for example made of flexible material, articulated meshes orother, which support and feed the core inside a tubular bar, from whicha plurality of bent portions are made.

In this variant solution, the core is moved by the movement means,axially to the tubular bar by a tail end of the latter, until theleading end is reached, and then positioned in cooperation with thebending arm of the bending means.

The movement of the tubular bar to bend its portions is, however,carried out head-wise.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

These and other characteristics of the present invention will becomeapparent from the following description of some preferential forms ofembodiment, given as a non-restrictive example with reference to theattached drawings wherein:

FIG. 1 is a schematized view, lateral and partially sectioned, of afirst form of embodiment of a machine for bending tubular elementsaccording to the present invention, in a first operating step;

FIG. 2 is a schematized view, lateral and partially sectioned, of thebending machine in FIG. 1, in a second operating step;

FIG. 3 is a schematized view, lateral and partially sectioned, of thebending machine in FIG. 1, in a third operating step;

FIG. 4 is a schematized view, lateral and partially sectioned, of asecond form of embodiment of a machine for bending tubular elementsaccording to the present invention, in a first operating step;

FIG. 5 is a schematized view, lateral and partially sectioned, of thebending machine in FIG. 4, in a second operating step;

FIG. 6 is a schematized view, lateral and partially sectioned, of thebending machine in FIG. 4, in a third operating step;

FIG. 7 is a schematized view, lateral and partially sectioned, of athird form of embodiment of a machine for bending tubular elementsaccording to the present invention, in a first operating step;

FIG. 8 is a schematized view, lateral and partially sectioned, of thebending machine in FIG. 7, in a second operating step;

FIG. 9 is a schematized view, lateral and partially sectioned, of thebending machine in FIG. 7, in a third operating step.

In order to facilitate comprehension, the same reference numbers havebeen used, where possible, to identify common elements in the drawingsthat are substantially identical. It is understood that elements andcharacteristics of one form of embodiment can conveniently beincorporated into other forms of embodiment without furtherclarifications.

DETAILED DESCRIPTION OF THE INVENTION

With reference to FIGS. 1, 2 and 3, a first form of embodiment of amachine 10 used for the bending of tubular elements, or tubes 11 isshown.

Both for this form of embodiment described and for the forms ofembodiment described hereafter, the relative representations aredeliberately schematic, in order to better understand thecharacteristics of the machine according to the present invention.

Operating details such as, for example, the diameters of the tubes, theradiuses of curvature achieved, the sizes of the core and others, havebeen deliberately chosen randomly so as not to constrain the individualforms of embodiment to specific operating solutions, also consideringthe fact that one of the main advantages of the present invention is theexcellent operating applicability of the bending machine substantiallyfor any type of tube with any radius of curvature.

In this case, the machine 10 comprises a bending member 12 and amovement member 13, in this case represented by an unwinding reel 23.The movement of the tube 11, in a manner known in the state of the art,is achieved by means of a motorized roller-way or with other systems ofan alternative type, such as a gripper, or similar means, not shown herein detail, which carry out both the first feed of the tubes 11 towardthe bending member 12 and the advance of the tubes 11 during the worksteps.

In the following description, the reference numbers 13, 113, 213 areused to indicate in general the member which moves the tube 11 linearlyin the direction of feed which, being known, is not shown in detail inthe drawings.

The machine 10 according to the present invention also comprises aholding member 15, the function of which will be described in detailhereafter.

The bending member 12 comprises a bend core 16 and a bending arm 17,which is mobile with respect to the bend core 16 in order to bend thetubes 11 fed.

In particular the bend core 16 is disposed inside the tubes 11 so as tofunction as contrast, inside the tube 11, to the bending action exertedexternally by the bending arm 17.

The bend core 16 comprises, in its turn, a polarized support bar 19, acontrasting ogive 20 and, in the case shown in the drawings, at least abend-follower element 21 disposed articulated at the head of thecontrasting ogive 20.

There may be only one bend-follower element 21, as in the drawings, orof the multiple type, or it may not be there at all, if the type ofbending and/or machine does not require it.

The bending arm 17 is of the substantially known type and is only shownschematized in the drawings. The bending arm 17 acts externally to thetube 11 to be bent in order to confer on the latter, in coordinationwith the advance imparted by the movement member 13, the bending radiusenvisaged. The bending aim 17 can be selectively positioned on differentplanes transverse to the direction F, in order to bend the tubes 11 ondifferent planes.

The machine 10 also comprises a cutting tool 22, for example a millingcutter or other, in this case, disposed downstream of the holding member15 and upstream of the bending member 12, which allows to cut to sizeone segment of tube 11, at the end of the bending steps.

Within the framework of the present invention, here and in the variantsolutions shown hereafter, it is understood that the cutting tool 22could also be disposed downstream of the bending member 12, or therecould be one or more cutting members 22 upstream and one or more cuttingtools downstream of the bending member 12.

The tube 11 is fed in the same direction of feed “F”, and in the samesense, both in the feed step of the tube 11 to the bending member 12,and also during the bending steps. The direction and sense of feeddefine a head-wise feed and a head-wise working of the tube 11.

The holding member 15 comprises at least a magnetic element 25; by thisterm we mean permanent magnets, electro-magnets or other similar orcomparable element. The magnetic element or elements 25 are disposedannularly around a zone in which the tube 11 is fed, in proximity to thebending member 12, defining an interspace between it and the bend core16 in which the tube 11 can be inserted.

The permanent magnets 25 thus disposed define, with their magneticfields, a median zone, axial to the direction of feed “F”, of magneticbalance. The bend core 16 is disposed with its support bar 19 in thismedian zone of magnetic balance. The support bar 19, being polarized,remains substantially suspended in correspondence to this zone, alsoabsorbing, among other things, the axial forces which they generateduring bending.

Therefore, the whole bend core 16 is maintained suspended by the actionof the magnetic fields generated by the permanent magnet or magnets 25,so as to allow the feed in the direction “F” required, without risk ofinterference with possible structures for the support of the bend core16 in its operating position.

As shown in sequence in FIGS. 1, 2 and 3, in this form of embodiment ofthe machine 10, the tube 11 is fed from a roll by the action of theunwinding reel 23 in the direction of feed “F”, and directed head-wisetoward the bending member 12.

Before reaching the bending arm 17, the leading end of the tube 11 ismade to pass inside the holding member in the interspace defined betweenthe permanent magnet or magnets 25 and the bend core 16, so that thelatter is disposed in suspension inside the tube 11.

In the form of embodiment shown in FIGS. 4, 5 and 6, a second form ofembodiment of the machine 110 according to the present invention isshown schematically.

In this case the machine 110 comprises a bending member 12, a movementmember 113, and a holding member 115, the latter two being of adifferent conformation than has so far been described.

The bending member 12 is the same as that described for the solution inFIGS. 1, 2 and 3, and comprises the bend core 16 and the bending arm 17,for bending the tubes 11 fed.

The movement member 113, in this case, comprises a motorized unwindingreel 23 able to unwind from a roll the tube 11 to be bent, and amovement pincers 123 disposed downstream of the unwinding reel 23 andupstream of the bending member 12, with respect to the direction of feed“F”.

In this case too there can be other feed members present, but not shownhere, such as a roller-way, etc.

In this variant solution too, the tube 11 is fed head-wise in the samedirection of feed “F”, and in the same sense, both by means of theunwinding reel 23 and also by means of the movement pincers 123.

The holding member 115 comprises a first gripping pincers 26 and asecond gripping pincers 27 disposed in cooperation with the bend core16, in order to keep it in a suspended condition, acting on one side ofthe tube 11.

In particular the first gripping pincers 26 is suitable to cooperatewith a tail end of the support bar 19 of the bend core 16; while thesecond gripping pincers 27 is suitable to cooperate with the contrastingogive 20 of the bend core 16. The operating sequence of the two grippingpincers 26 and 27 will be described in detail hereafter.

The machine 110 in this case also comprises a cutting tool 122, forexample a milling cutter or other, in this case disposed upstream of thefirst gripping pincers 26, and able to cut to size a segment of tube 11before bending.

As shown in sequence in FIGS. 4, 5 and 6, in this form of embodiment ofthe machine 110, the tube 11 is initially unwound from a roll by theaction of the unwinding reel 23, and moved in the direction of feed “F”by the feed member 113, and directed head-wise toward the bending member12.

During the feed of the tube 11, the bend core 16 is kept in a suspendedcondition by the action of the second gripping pincers 27.

Before reaching the second gripping pincers with the leading end of thetube 11, the unwinding reel 23 stops the feed of the tube 11 and thecutting tool 122 cuts to size the segment of tube 11 to be bent. Beforethe definitive cut of the segment of tube 11, the segment is associatedto the movement pincers 123. In a variant of this solution two cuttingunits can be provided, in which a first cuts one segment made frommultiples of the product, and a second is positioned after the bendingmember 12 and cuts to size the bent tube.

Once the cutting to size has been carried out, the unwinding reel 23partly recovers the tube 11, separating from the cut segment, andfreeing a back section of the support bar 19 of the bend core 16.

In this condition, the first gripping pincers 26 is brought intocooperation with this back section of the support bar 19, andsubsequently the second gripping pincers 27 is discharged, releasing thecontrasting ogive 20.

At this point the movement pincers 123 feed the segment head-wise in thedirection F in the same sense of feed executed with the unwinding reel23, so as to bring it into cooperation with the bending member 12 andperform the required bends.

In the form of embodiment shown in FIGS. 7, 8 and 9, the bending machineaccording to the present invention is shown in its entirety with thereference number 210.

In this case the machine 210 comprises a bending member 12, a movementmember 213, and a holding member 215, the latter two having aconformation different from both the solutions so far described.

The bending member 12 is the same as that described for the previoussolutions and comprises the bend core 16 and the bending arm 17.

In this case the tube, rather than being fed from a roll, is fed in bars211 of a length substantially multiple to the length of the individualsegments to be bent.

In this case, the movement member 213 comprises movement pincers 223disposed in cooperation with a back end of the bar 211, in order todetermine a movement thereof toward the bending member 12 in thedirection of feed F.

The holding member 215 comprises a support bar 219 directly connected tothe back part of the contrasting ogive 20 of the bend core 16.

The support bar 219 is made of flexible material, with articulatedmeshes or other, so as to be able to feed the contrasting ogive 20 fromthe back surface of the tubular bar 211, with a curvilinear path, and inany case guarantee sufficient rigidity in the operating position of thecontrasting ogive 20.

The machine 210 in this case also comprises a cutting tool 222, forexample a milling cutter or other, in this case disposed upstream of thebending arm 17, and able to cut to size a segment of tube 11 afterbending.

As shown in sequence in FIGS. 7, 8 and 9, in this form of embodiment ofthe machine 210, the tubular bar 211 is initially fed from a store anddisposed in the direction of feed F. From here the movement pincers 223feed the bar 211 head-wise toward the bending member 12.

Once the bar 211 is disposed in cooperation with the bending member 12,the bend core 16 is inserted axially to the bar 211 from a back end ofthe latter, until it reaches the position of cooperation, inside the bar211, with the bending arm 17.

The bar 211 is then progressively fed by the movement pincers 233 tocarry out the desired bends.

At the end of bending, the cutting tool 222 cuts the segment to size, inorder to resume the bending cycle of a new section of the bar 211,always fed head-wise.

It is clear that modifications and/or additions of parts or steps may bemade to the machine 10 and the cutting method as described heretofore,without departing from the field and scope of the present invention.

For example, it comes within the scope of the present invention toprovide that cutting tools 22, 122, 222 are disposed downstream of thebending member 12, or in another position with respect to the bendingmember 12, depending on the different operating conditions.

According to another variant, the support bar 19 is polarized by meansof a magnetic core, or an electric current or other known polarizationsystem, able to generate a magnetic field contrasting the action of thefield generated by the permanent magnets 25, or by the electro-magnets.

It is also clear that, although the present invention has been describedwith reference to some specific examples, a person of skill in the artshall certainly be able to achieve many other equivalent forms ofmachine for bending tubular products and relative cutting method, havingthe characteristics as set forth in the claims and hence all comingwithin the field of protection defined thereby.

1. A machine to bend tubular elements comprising bending means providedwith at least a bending arm and a bend core disposed, when in use,inside said tubular element, the bend core comprising a support bar, acontrasting ogive and a possible bend-follower element disposedarticulated at the head of the contrasting ogive, the machine alsocomprising movement means, to move said tubular element in a directiontoward said bending means, and cutting means to cut a segment of tube,wherein it also comprises holding means disposed on the perimeter aroundsaid tubular element and configured to maintain said bend core in acondition of suspension inside said tubular element.
 2. The machine asin claim 1, wherein the movement means are of the type with an unwindingreel and the holding means are of the magnetic type and comprise atleast a magnetic element disposed downstream of said unwinding reel inthe direction and outside and around the tubular element, so as togenerate a magnetic field cooperating with said support bar and to keepthe bend core in magnetic suspension inside said tubular element.
 3. Themachine as in claim 2, wherein said support bar is provided with amagnetic polarization.
 4. The machine as in claim 2, wherein saidmagnetic elements and said bend core define between them an interspaceinto which the tubular element is inserted around said bend core.
 5. Themachine as in claim 1, wherein the feed means are of the combined type,with an unwinding reel and a movement gripper, and the holding meanscomprise a first gripping member, disposed on one side of the perimeterof the tubular element in cooperation with a first end of the bend core,in order to selectively keep said bend core in the suspended conditioninside the tubular element during the feed steps of said tubular elementin the direction of feed and toward said bending means, and a secondgripping member, distanced longitudinally from said first grippingmember, and disposed in cooperation with a second end of the bend core,and able to keep the bend core in the suspended condition inside thetubular element during the bending steps of said tubular element, inwhich the tubular element is moved by said grippers.
 6. The machine asin claim 5, wherein it comprises at least a cutting member disposedupstream and/or downstream of the gripping member with respect to thedirection of feed, and able to divide the tubular element into segmentsof the desired length.
 7. A method to bend tubular elements comprisingat least a bending step, in which bending means provided with at least abending arm act on an external surface of said tubular element, and abend core disposed inside said tubular element contrasts the action ofsaid bending arm from the inside and conforms the bend of said tubularelement in a desired manner, and at least a movement step in whichmovement means move said tubular element both to feed it toward saidbending means and also during the bending step, wherein, both in saidbending step and also in said movement step, said bend core ismaintained in a condition of suspension inside said tubular element bymeans of holding means, disposed on the perimeter around said tubularelement.
 8. The machine as in claim 2, wherein it comprises at least acutting member disposed upstream and/or downstream of the grippingmember with respect to the direction of feed, and able to divide thetubular element into segments of the desired length.